The present invention is generally directed to autostereoscopic picture production and in particular to such production employing lenticular print material, whereby a novel method and apparatus are disclosed for composing a three-dimensional print from a number of two-dimensional views of an object field without requiring precise control of the lens-film arrangement.
A known method for composing such prints uses a conventional two-dimensional camera to photograph an object field from different vantage points, thereby producing a negative film whose frames each contain a view of the object field from the respective vantage point at which the frame was exposed. These two-dimensional views are then projected sequentially or simultaneously by an imaging system through a lenticular screen to expose the photosensitive emulsion beneath the lenticules.
In connection with these known three-dimensional printing processes, the lenticular print material employed therewith ordinarily requires each of the frames of the negative film to be exposed within an assigned angular zone. The sum total of all of the angular exposure zones is chosen so as to match what is commonly termed the acceptance angle of the lenticule. This acceptance angle is simply the arcuate zone to which any incoming light must be restricted in order to properly expose the photosensitive material beneath the lenticule. In order to achieve this angular zone exposure, one prior art technique employs a dynamic film-lens arrangement whereby the film and lens move during exposure to continuously scan each frame across its assigned angular exposure zone, commonly known as proportional scanning. A detailed discussion of this method is found in U.S. Pat. No. 4,120,562.
This known angular exposure technique requires precise proportional tracking of the relative motion of the lens and film, as well as minimal amounts of lens distortion in order to provide substantially uninterrupted and nonoverlapping image bands on the lenticular film, while matching the acceptance angle of the lenticular print film. Such dependency upon precise control of the lens-film arrangement subjects this known method to other factors, e.g. vibration, which tend to lessen the quality of the print.
Further disadvantages of prior art composing methods and the machinery used to implement them include difficult and expensive manufacturing and maintenance techniques, as well as frequent calibration and an inherently large size.